1. Field of the Invention
The present invention is generally related to oil reservoirs and to induction noise silencing components and, more particularly, to an oil reservoir which is shaped for use as an induction noise silencer for an internal combustion engine.
1. Description of the Prior Art
Many different components and parts of an internal combustion engine generate vibration and noise. In addition to the reciprocating pistons, which can create vibration in the engine, and the exhaust stream of rapidly moving hot gases, the air induction system of an engine can be one of the most significant sources of noise. Air must be drawn into the one or more throttle bodies of the engine for use in the combustion and scavenging processes. Whether the internal combustion engine is carbureted or fuel injected, large quantities of air must be inducted into the combustion chambers.
As ambient air is drawn toward and into the one or more throttle bodies, noise is created. In addition, sound produced by the internal components of the engine can be emitted through the throttle bodies because, in most cases, the throats of the throttle bodies represent the most direct and least impeded path for the noise to travel from the internal components of the engine to the region surrounding the engine.
Many types of internal combustion engines are provided with oil tanks, or reservoirs, in which a quantity of oil is stored for use by the engine. In some situations, such as in certain outboard motors for marine use, an oil tank is located under the cowl which covers the engine. In some applications, the oil reservoir under the cowl operates as a holding tank and is connected in liquid communication between the engine and a larger oil tank located elsewhere on the marine vessel.
In the design of outboard motors, the space under the cowl of the outboard motor is very limited. In known outboard motors, some of this valuable space under the cowl must be used for the oil reservoir and other valuable space must be used for some type of noise silencer located near the one or more throttle bodies in order to attenuate the noise emanating from the throttle bodies.
In systems known to those skilled in the art, many different techniques and processes have been used to reduce the noise of internal combustion engines and, more specifically, outboard motors. Also, many different designs of oil reservoirs are known to those skilled in the art of internal combustion engines and outboard motors.
U.S. Pat. No. 5,487,688, which issued to Sumigawa on Jan. 30, 1996, describes an outboard motor and several embodiments which embody four cycle engines having an oil tank that is contained within the driveshaft housing and which is surrounded at least in part by a water cooling jacket for maintaining the oil at an acceptable temperature. The oil tank is formed with a cavity through which an exhaust pipe passes and the area between the exhaust pipe and the oil tank forms, in at least some embodiments, an expansion chamber for silencing the exhaust gases. At least part of the exhaust pipe and/or expansion chamber is also cooled by a water jacket.
U.S. Pat. No. 5,373,824, which issued to Peters et al on Dec. 20, 1994, describes an acoustical damping device for gaseous fueled automotive engines. The fuel supply system for a gaseous fueled automotive engine is provided for means for damping pressure waves occurring within the fuel line between the fuel tank and the engine. In a preferred embodiment, acoustical barriers, such as annular rings, are secured to the inside of the fuel rail for partially transmitting and partially reflecting the pressure waves so that wave amplitude is decreased. An alternative embodiment comprises an acoustical barrier in the fuel line having an cylindrical section with a diameter larger than that of the fuel line. Baffles, possibly annular rings, within the cylindrical section also serve to damp the pressure waves. The acoustical barrier may also be composed of a conical section with diameters equal to that of the cylindrical section on one end and the fuel line at the other end. Acoustical barriers placed in both the fuel line and fuel rail also effectively damp the pressure waves.
U.S. Pat. No. 4,215,664, which issued to Hatz on Aug. 5, 1980, discloses an internal combustion engine with a sound-proofing shell. In order to compensate for positional variations during assembly or in use between an engine body or crankcase and a sound-proofing shell enclosing the same, use is made of interposed spring arrangements including a load-setting means.
The above described patents are hereby expressly incorporated by reference in this description.
It would be significantly beneficial if a means could be provided to combine the functions of oil storage under the cowl and noise silencing under the cowl into a single component or structure. This would perform both individual functions while also significantly reducing the required space under the cowl of an outboard motor.